Process of removing rust and inhibiting further rusting



Patented Oct. 5, 1954 UNITED STATES ATENT OFFICE PROCESS OF REMOVINGRUST AND INHIBITING FURTHER RUSTING The Kromite Products Company,Bedford,

Ohio, a corporation of Ohio No Drawing. Application April 23, 1952,Serial No. 283,980

2 Claims.

The plating of ferrous surfaces with chromium and the like for finishand prevention of rust is universal. However, even with this there is atendency for iron rust stain to appear in the course of time, and thistendency is greatly increased in the case of automobiles by theprevalent use of salt and calcium chloride as snowmelting material onstreets. In accordance with the present invention, rust stains on platedsurfaces may be removed, and by material which also inhibits recurrence.Excessive polishing and wear for maintaining desired appearance ofplated surfaces thus becomes unnecessary, and with increase in longevityof the plate coat. Other objects and advantages will appear from thefollowing description.

To the accomplishment of the foregoing and related ends, said inventionthen comprises the features hereinafter fully described and particularlypointed out in the claims, the following description setting forth indetail certain illustrative embodiments of the invention, these beingindicative, however, of but a few of the various ways in which theprinciple of the invention may be employed.

We have found that by subjecting plated surfaces which are rust-stained,to treatment with material as further detailed below, the rust isremoved, and at the same time the surface receives a protection whichprevents ready recurrence of staining. We have found that polycalciumcompounds, particularly polycalcium silicate if properl applied to arust-stained surface, such as of chromium plating, readily clears such.Tricalcium silicate is particularly contemplated. With this there may bea component of dicalcium silicate, and of tricalcium aluminate.Compositions containing tricalcium silicate and tricalcium aluminate arehereinafter concisely termed polycalcium silicate and aluminate. Suchmaterial in finely powdered form is applied to the rust stained surfacein the presence of water, and it is important that a time interval beallowed between the bringing together of the material and the water,sufficient to allow action therebetween, before the material is appliedto the plated surface. Thus, in preferred procedure, an applying fabricis wet with Water, not in excess, and the powder is dusted or poured onthe wet fabric. This is allowed to stand for some moments, approximatelya minute. Then, such surface is rubbed onto the rust-stained platinglightly, and the rust clears off, and the plating is then immediatelywiped dry. The nature and reason for the action is obscure and notdefinitely known,

and we are not bound by any theory, but there is reason to believe thatin the presence of the moistening water the tricalcium silicate goesover into monocalcium silicate and calcium hydroxide. The latter ishigher in the E. M. F. scale, and is able to affect the iron oxide orrust. The minute holes through the plate coat, by which the permeationand oxidation of the iron base occurred, are apparently then filled andsealed oif by the by-products of the residue. Irrespective of anyattempted theorization however, the practical fact is that badlyrust-stained surfaces as of chromium plate are quickly cleared, and thesurprising further effect is that the bright appearance persists, ratherthan soon requiring additional polishing.

Polycalcium aluminate has effective action to a lesser extent than theaforementioned silicates, and may be used in conjunction therewith. Acombination of tricalcium silicate, dicalcium silicate and tricalciumaluminate, powdered, is of practical utility, and it is possible toprovide such without excessive preparation cost by making use of thematerials available on the market. Tricalcium silicate and dicalciumsilicate, with or without tricalcium aluminate can be prepared as inknown manner by heating limestone and clay in intimate mixture, to atemperature providing incipient fusion or sintering, the raw materialsbeing preliminarily ground and slurried, and then fired, and finallyground to desired mesh. This should be on the order of 200 mesh orfiner. Limestone and clay ground and slurried and burned as on the orderof Portland cement also provides an approximation. In general, ifcalcium aluminate in addition to the polycalcium silicates is desired,such a composition may have a ratio CaO The ratio of silica and aluminamay be in such material between about 2.5 and 4. In any event,tricalcium silicate is contemplated particularly, and the othercompounds as stated may be additional. Impurities such as iron oxide,magnesium oxide, etc., should be absent or minimal, not exceeding a fewpercent.

The line powdered treating agent, as aboveindicated, in any case is tobe applied to the surface to be treated, by first allowing a few momentstime for action with the moistening water preliminarily. And, such timeshould not be excessive, as the efliciency of results then may belessened.

As an example: A wiping cloth, as for instance customary cheese-cloth,is wet with water and dripping-excess removed, and powdered tricalciumsilicate, with which may be dicalcium silicate and tricalcium aluminate,is applied in layer which can be well wet by the water carried by thefabric. The Water is allowed to act for a few moments up to about aminute, and then the ruststained automobile bumper or the like to becleaned is lightly rubbed with such fabric for removal of the rust. Thesurface is wiped dry, and nascently-formed hydrated silica residue, andalumina if present, fills and seals pervious pinholes in the plate coat.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

We therefore particularly point out and distinctly claim as ourinvention:

1. In a process of treating plated metal surfaces, eliminating rust froma chromium-plated surface on an iron base by applying moistening Waterand a small amount of polycalcium silicate and aluminate powder to afabric, allowing action between the moistening water and powder for afew moments, then lightly rubbing such fabric on the rust-affected ironbase chromium plated metal surface, and wiping dry.

2. In a process of treating metal surfaces, eliminating rust from achromium-plated surface on an iron base by wetting a fabric, applyingthereto a powder of polycalcium silicates and aluminate, allowing actionbetween the moistening water and powder for a few moments, then lightlyrubbing such fabric on the rust-affected iron base chromium plated metalsurface, and wiping dry.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,143,614 Criswell June 22, 1915 1,526,149 Jackson Feb. 10,1925 1,729,765 Dinley Oct. 1, 1929 2,403,821 Morgan July 9, 1946 OTHERREFERENCES Partington: Textbook of Inorganic Chemistry, 6th ed., 1950;pub. McMillan and Co., London, page I60. Copy Scientific Library.

1. IN A PROCESS OF TREATING PLATED METAL SURFACES, ELIMINATING RUST FROMA CHROMIUM-PLATED SURFACE ON AN IRON BASE BY APPLYING MOISTENING WATERAND A SMALL AMOUNT OF POLYCALCIUM SILICATE AND ALUMINATE POWDER TO AFABRIC, ALLOWING ACTION BETWEEN THE MOISTENING WATER AND POWDER FOR AFEW MOMENTS, THEN LIGHTLY RUBBING SUCH FABRIC ON THE RUST-AFFECTED IRONBASE CHROMIUM PLATED METAL SURFACE, AND WIPING DRY.